The invention relates to microbial gaseous-fluid sampler and methods of operating the same. Commonly, such microbial gaseous-fluid samplers can be microbial air samplers operable to capture bacteria, fungi, and other particles onto a Petri dish loaded with nutrient agar. The sample captured onto the Petri dish can be grown into colonies. The colonies formed after incubation are counted to determine the concentration of colony forming units (CFU's).